Multiple databases in docker and docker-compose

According to this Github issue might be possible to achieve multiple databases by using bash scripts which you will have to pass in your Dockerfile

EDIT:

To create multiple Databases you could use the following script:

https://github.com/mrts/docker-postgresql-multiple-databases

or

https://github.com/MartinKaburu/docker-postgresql-multiple-databases

Which suggest that you have to clone one of the above git repos and mount it as a volume to: /docker-entrypoint-initdb.d then you would be able to pass multiple database names by using: POSTGRES_MULTIPLE_DATABASES variable

Usually when I need more than one database in a docker project it's a test database. I find it easier to simply spin up a second docker container, without worrying about scripts or volume separation.The main trick is to not conflict the default ports (e.g. 5432 for postgres) and you're good to go.Then docker-compose can be something as simple as this:

version: '3.0'services:   db:    image: postgres    environment:       - POSTGRES_DB      - POSTGRES_USER      - POSTGRES_PASSWORD    ports:      - ${POSTGRES_DEV_PORT}:5432    volumes:      - app-volume:/var/lib/postgresql/data  db-test:    image: postgres    environment:       - POSTGRES_DB      - POSTGRES_USER      - POSTGRES_PASSWORD    ports:      - ${POSTGRES_TEST_PORT}:5432    # Notice I don't even use a volume here since I don't care to persist test data between runsvolumes:  app-volume: #

Well - take a look at this Github project: https://github.com/mrts/docker-postgresql-multiple-databases

According to official postgres docker image documentation:

If you would like to do additional initialization in an image derived from this one, add one or more *.sql, *.sql.gz, or *.sh scripts under /docker-entrypoint-initdb.d (creating the directory if necessary). After the entrypoint calls initdb to create the default postgres user and database, it will run any *.sql files and source any *.sh scripts found in that directory to do further initialization before starting the service.

You will find the prepared script on that repo which you could use.